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2001 8.1/Allison tranny shudder

sparky

By sparky
in 2000-2014 Silverado HD & Sierra HD

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sparky New Member

sparky

Posted
Posted

A little long, but I need to give good info. Back in April I took my truck to the dealer to do updates on the Allison tranny. Torque converter bolts, park/neutral switch, and change a spring. When I got the truck back it seemed a little different, but I couldn't put my finger on it. After driving it awhile I noticed a little shudder. I drove it for a couple of months hoping it would go away. Finally, I took it to the dealer and they agreed it wasn't right. They removed it and sent it to a tranny shop that was familiar with Allison. He tore it down and checked out the work the dealer had originally done and said it was right.

He got on the phone to Allison and spent quite abit of time with them. They decided to install a high-performance shift kit by Transgo. This was done and the tranny was re-installed in the truck. They re-flashed the PCM and re-set the taps in the TCM but couldn't find a Quick learn for the TCM. The truck still shudders between 1-2 and 2-3 and sometimes all the gears! Sometimes it doesn't shudder at all, especially when it's cold! If anybody has had this same problem, I sure would like to know the fix!. My warranty had run out, but the dealer extended it for 2 more years. It has 32,000 mi. on it with about 3000 with the shudder. Mostly I use it for towing my 30' camper, but it does it in tow/haul as well as regular mode. The line pressures are good also. Any info would be appreciated!

ctfan Enthusiast

ctfan

Posted
Posted

This might be a far fetched idea and maybe not possible but could the driveshaft for some reason become unbalanced. Or I would also suggest the u joints

zorrro Enthusiast

zorrro

Posted
Posted

I would really like some info on this too. My '01 does this with the 8.1 Allison. Every time I take some time to pay real close attention to it, it decides not to shudder. When I'm haulin' the whole family somewhere and crunched for time the problem always pops up? Keep us posted..............Zorrro

  • 2 weeks later...
Tel9000 New Member

Tel9000

Posted
Posted

My Duramax with a 6 in lift had a shudder after takeoff. The Superlift Dealer installed a carrier drop on the two piece driveshaft and it went away.

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